Last updated 24 March 2024


Episode Four

Series Episode Number: 247

World Premiere: Sat 10 May 1969 - 5:15pm BST [BBC One] (United Kingdom)
First Broadcast: Sun 30 Nov 1986 - 11:25pm CST [WTTW 11 Chicago]
Running Time: 23 minutes 30 seconds

5.70 Million (UK)

Appreciation Index: 50 (UK)

Chart Position: 63 () (UK)

Recorded on Fri 02 May 1969 in Television Centre 4
Archive State: 16mm t/r



The Doctor and Zoe penetrate the Aliens' HQ from where the war games are controlled. Carstairs is reconditioned and exposes the Doctor and Zoe as German spies.


Production Team hide uncredited
WriterMalcolm Hulke
WriterTerrance Dicks
DirectorDavid Maloney
ProducerDerrick Sherwin
DesignerRoger Cheveley
Incidental MusicDudley Simpson
Title MusicRon Grainer
Film CameramanAlan Jonas (uncredited)
Film EditorChris Hayden (uncredited)
LightingHoward King (uncredited)
SoundJohn Staple (uncredited)
CostumesNicholas Bullen (uncredited)
Make-upSylvia James (uncredited)
Visual Effects DesignerMichaeljohn Harris (uncredited)
Special SoundBrian Hodgson (uncredited)
Title Music BBC Radiophonic Workshop (uncredited)
Fight ArrangerPeter Diamond (uncredited)
Fight ArrangerArthur Howell (uncredited)
Assistant Floor ManagerMarion McDougall (uncredited)
Production AssistantEdwina Verner (uncredited)
Film Camera AssistantJohn Walker (uncredited)
Film Sound RecordistBill Meekums (uncredited)
Assistant Sound RecordistAlan Cooper (uncredited)
Script EditorTerrance Dicks (uncredited)
Title Music ArrangerDelia Derbyshire (uncredited)
Effects AssistantDave Havard (uncredited)
Title SequenceBernard Lodge (uncredited)
Technical ManagerFred Wright (uncredited)
Vision MixerDavid Langford (uncredited)
Technical ManagerDavid Hare (uncredited)